The parent SCOR Program has developed the necessary facilities, organizational mechanisms, investigative expertise, and planned research to advance understanding of the causes and prevention of atherosclerosis. The research program is a broadly based interdisciplinary attack on numerous aspects of the disease process. Particular emphasis is placed on genetic and biochemical mechanisms in determining hypo or hyperresponsiveness of nonhuman primates to dietary cholesterol, comparative studies of pleomorphic features of fatty streaks, studies on endothelial permeability, lesion regression and vascular function of atherosclerotic rhesus monkeys, the structure and function of lipoproteins as affected by diet and heredity, studies on arterial metabolism, and finally, a new project concerned with factors which diminish or abolish the protection of female primates against coronary artery atherosclerosis. In this supplemental application we propose to continue for two additional years a project entitled "Evaluation of Sites of Genetic Control of Plasma Cholesterol Concentrations in Hypo- and Hyperresponding Nonhuman Primates". The research will utilize defined nonhuman primates, will involve studies of cholesterol absorption, cholesterol excretion and the relationship of this phenomena to various aspects of lipoprotein metabolism.